Image sensors are widely used in digital still cameras, cellular phones, security cameras, medical, automobile, and other applications. Complementary metal-oxide-semiconductor (“CMOS”) technology is used to manufacture low-cost image sensors on silicon substrates.
Most CMOS image sensors include a two-dimensional array of pixels that are used to capture images. The pixel array is usually formed in and/or on a substrate along with various support circuits. The support circuits, as their name implies, support the operations of the pixel array to capture images. In many cases the substrate in which the pixel array and support circuits are formed is a semiconductor. Some types of support circuits can generate noise of sufficient levels that the noise can be transmitted electrically through the semiconductor substrate and adversely influence the operation of more noise-sensitive components such as the pixel array.